Polaris 3900 Sport Wheel Sprocket Assembly w/ Bearing (39-420)
The wheel sprocket assembly w/ bearing is a replacement part made by Polaris. The same high-grade plastic material was used to create the original factory part. It can perform the same way as well ensuring that you are purchasing a genuine OEM part.
There are two of these sprockets that are needed to be able to give the cleaner the ability to move along the surface with the two bearings located on the back of them. They are black with teeth that run along the outside intended for the chain to be placed and operate. Rotating them in a circular motion while also rotating the wheels themselves.
One good troubleshooting tip if the sprockets are not rotating the way they were intended to, could be caused by the bearings going bad. Meaning they would need to be replaced to restore the normal operating functionalities back to the cleaner.